I'm surprised no one brought up that Rookie of the Year thing.
Or the fact that Rookie quarterbacks aren't expected to play at all. And quarterbacks in their 3rd year are supposed to start getting good.
This dude enters the NFL like NO ONE else at the QB position.
Then he wins a SB (with a good defense), sets the Steelers TD records, wins another SB (that was ALL him - you should have watched him play behind that O-Line all season), and now halfway through the season he has 14 TDs, 70% accuracy, and 2000+ yards. His accuracy over the years is off the hook. And he has more comeback wins than any other QB in the last 5 years.
So it comes down to this: either you've actually watched him play and you know what you're talking about, or you spent your time watching Alex Smith/JaMarcus Russel/Matt Leinart/Matt Hasselbeck, and haven't had time to watch a good QB.